"If you don't shake off slumps, you're not very good,'' Pedroia said after having a direct role in Boston's 6-2 win over Arizona at Fenway Park.

"I've hit every year of my life. I don't think that's ever going to stop.''

Pedroia's two-run homer in the first gave a quick lead to Jon Lester (8-2), who remained unbeaten since April 18.

A leadoff single in the third led to two more runs.

"You're always trying to score some early runs to let your pitcher go to work. Jon took it from thre,'' said Pedroia, who went 2-for-4.

"Scoring early runs and putting pressure on the other team is the sign of a good club,'' centerfielder Mike Cameron said.

"We've been doing that, and our pitching has been outstanding.''

Pedroia is on a 12-for-24 hitting streak that followed a 23-for-108 skid in May.

An MRI on his aching right knee last week helped his confidence, for no serious damage was found.

He has raised his average 20 points to .271.

He also stole his fifth base, and made a snazzy first-inning defensive play.

Pedroia said the good news from the MRI was not needed to give him confidence to run.

Steal attempts force defenses to react, opening up holes in the infield.

"I'm always looking to run. We've got a lot of left-handed hitters behind me, and they like to look for that hole.''

The Red Sox will go for a three-game series sweep Thursday.

"That would be nice, but they've got a tough pitcher (Dan Haren) going. We've got to come out and play,'' Pedroia said.

The Diamondbacks have lost a club record 12 straight road games. They hit Lester hard in the early innings, but he pitched out of a tight spot in the fourth, then retired 11 of the last 12 men he faced.

The left-hander lowered his ERA to 3.13. Lester is 8-0 with three no-decisions since April 18.

His ERA in that time is 2.01, with 82 strikeouts in 76 innings.

Against Arizona, Lester allowed four hits in seven innings.

He had three walks and two hit batsmen, but also fanned seven in a 103-pitch effort.

Three of the four hits he allowed came in the second, when Justin Upton's home run created a 2-2 tie.

The other hit came in the fourth, when Arizona loaded the bases with one out.

But Lester fanned Rusty Ryal, Chris Snyder flied out, and the Diamondbacks went quietly after that.

Lester remained one victory behind Clay Buchholz for the team lead.

These two pitchers may find themselves competing for American League All-Star spots.

Buchholz and Lester pitched similarly in this series.

Each labored in the early innings, but held the fort before turning the game over to a bullpen that finished it off.

In Lester's case, his job was finished by Daniel Bard, Ramon Ramirez and for the last out, Jonathan Papelbon.

After giving up two runs in the third for a 4-2 deficit, Arizona's Rodrigo Lopez (2-6) settled down to keep it close.

Manager A.J. Hinch tried to ride Lopez through the seventh. That might have been a mistake.

His 104th pitch came in the seventh, when Kevin Youkilis' two-run homer made it 6-2.